The present invention relates to the use of dihydropyrimidines as medicaments, to novel substances, to processes for their preparation, in particular as medicaments for the treatment and prophylaxis of hepatitis B.
The publication EP 103 796 A2 already discloses dihydropyrimidines having a circulation-influencing effect.
Surprisingly, it has now been found that dihydropyrimidines of the general formula (I) 
or their mesomeric form (Ia) 
in which
R1 is phenyl, furyl, thienyl, triazolyl, pyridyl, cycloalkyl having from 3 to 6 carbon atoms or is a radical of the formula 
where the abovementioned ring systems are optionally mono- or polysubstituted, identically or differently, by substituents chosen from the group consisting of halogen, trifluoromethyl, nitro, cyano, trifluoromethoxy, carboxyl, hydroxyl, (C1-C6)-alkoxy, (C1-C6)-alkoxycarbonyl and (C1-C6)-alkyl which in turn can be substituted by aryl having from 6 to 10 carbon atoms or halogen,
and/or the above ring systems are optionally substituted by groups of the formulae xe2x80x94Sxe2x80x94R6, NR7R8, COxe2x80x94NR9R10, SO2xe2x80x94CF3 and xe2x80x94Axe2x80x94CH2xe2x80x94R11,
wherein
R6 is phenyl, which is optionally substituted by halogen,
R7, R8, R9 and R10 are identical or different and are hydrogen, phenyl, hydroxy-substituted phenyl, hydroxyl, (C1-C6)-acyl or (C1-C6)-alkyl, which for its part may be substituted by hydroxyl, (C1-C6)-alkoxycarbonyl, phenyl or hydroxy-substituted phenyl,
A is a radical O, S, SO or SO2,
R11 is phenyl, which is optionally mono- or polysubstituted, identically or differently, by substituents chosen from the group consisting of halogen, nitro, trifluoromethyl, (C1-C6)-alkyl and (C1-C6)-alkoxy,
R2 is a radical of the formula xe2x80x94XR12 or xe2x80x94NR13R14,
wherein
X is a bond or oxygen,
R12 is hydrogen, straight-chain or branched (C1-C6)-alkoxycarbonyl or a straight-chain, branched or cyclic, saturated or unsaturated (C1-C8)-hydrocarbon radical, which optionally contains one or two identical or different hetero chain members from the group consisting of O, CO, NH, xe2x80x94NHxe2x80x94(C1-C4)-alkyl, xe2x80x94Nxe2x80x94((C1-C4)-alkyl)2, S and SO2, and which is optionally substituted by halogen, nitro, cyano, hydroxyl, aryl having from 6 to 10 carbon atoms or aralkyl having from 6 to 10 carbon atoms, heteroaryl or a group of the formula xe2x80x94NR15R16,
wherein
R15 and R16 are identical or different and are hydrogen, benzyl or (C1-C6)-alkyl,
R13 and R14 are identical or different and are hydrogen, (C1-C6)-alkyl or cycloalkyl having from 3 to 6 carbon atoms,
R3 is hydrogen, amino or is a radical of the formula 
is formyl, cyano, hydroxy-substituted (C1-C6)-alkylthio, trifluoromethyl or pyridyl, or
is a straight-chain, branched or cyclic, saturated or unsaturated hydrocarbon radical having up to 8 carbon atoms, which is optionally mono- or polysubstituted, identically or differently, by aryloxy having from 6 to 10 carbon atoms, azido, halogen, cyano, hydroxyl, carboxyl, (C1-C6)-alkoxycarbonyl, a 5- to 7-membered heterocyclic ring, (C1-C6)-alkylthio or (C1-C6)-alkoxy, which for its part can be substituted by azido or amino, and/or is substituted by triazolyl, which for its part can be substituted up to 3 times by (C1-C6)-alkoxycarbonyl,
and/or can be substituted by groups of the formula xe2x80x94OSO2xe2x80x94CH3 or (CO)axe2x80x94NR17R18,
wherein
a is a number 0 or 1,
R17 and R18 are identical or different and are hydrogen or aryl, aralkyl having from 6 to 10 carbon atoms,
or are (C1-C6)-alkyl, which is optionally substituted by (C1-C6)-alkoxycarbonyl, amino, hydroxyl, phenyl or benzyl, where phenyl or benzyl are optionally mono- or polysubstituted, identically or differently, by hydroxyl, carboxyl, (C1-C6)-alkyl or (C1-C6)-alkoxy,
or (C1-C6)-alkyl is optionally substituted by groups of the formula NHxe2x80x94COxe2x80x94CH3 or NHxe2x80x94COxe2x80x94CF3,
or
R17 and R18 together with the nitrogen atom form a morpholine, piperidinyl or pyrrolidinyl ring,
or
R3 is phenyl, which is optionally substituted by methoxy,
or
R2 and R3 together form a radical of the formula 
R4 is hydrogen, (C1-C4)-alkyl, (C1-C4)-alkenyl, benzoyl or is acyl having from 2 to 6 carbon atoms,
R4 is hydrogen, methyl, benzoyl or is (C2-C6)-acyl,
R5 is pyridyl, pyrimidyl or pyrazinyl,
and their salts,
surprisingly have an antiviral action against hepatitis B (HBV) and are therefore suitable for the prophylaxis and control of virus-induced illnesses, in particular of acutely and chronically persistent HBV virus infections.
For the purposes of the invention, cycloalkyl having from 3 to 6 carbon atoms is cyclopropyl, cyclopentyl, cyclobutyl or cyclohexyl. The following may be mentioned in preference: cyclopentyl or cyclohexyl.
Aryl is generally an aromatic radical having from 6 to 10 carbon atoms. Preferred aryl radicals are phenyl and naphthyl.
For the purposes of the invention, (C1-C6)-acyl is a straight-chain or branched acyl radical having from 1 to 6 carbon atoms. Preference is given to a straight-chain or branched acyl radical having 1 to 4 carbon atoms. Particularly preferred acyl radicals are acetyl and propionyl.
For the purposes of the invention, (C1-C6)-alkyl is a straight-chain or branched alkyl radical having 1 to 6 carbon atoms. Examples which may be given are: methyl, ethyl, propyl, isopropyl, tert-butyl, n-pentyl and n-hexyl. Preference is given to a straight-chain or branched alkyl radical having from 1 to 4 carbon atoms.
For the purposes of the invention, (C2-C6)-alkenyl is a straight-chain or branched alkenyl radical having from 2 to 6 carbon atoms. Examples which may be given are: ethenyl, propenyl, isopropenyl, tert-butenyl, n-pentenyl and n-hexenyl. Preference is given to a straight-chain or branched lower alkenyl radical having from 3 to 5 carbon atoms.
For the purposes of the invention, (C1-C6)-alkoxy is a straight-chain or branched alkoxy radical having from 1 to 6 carbon atoms. Examples which may be given are: methoxy, ethoxy, propoxy, isopropoxy, tert-butoxy, n-pentoxy and n-hexoxy. Preference is given to a straight-chain or branched alkoxy radical having from 1 to 4 carbon atoms.
For the purposes of the invention, (C1-C6)-alkoxycarbonyl is a straight-chain or branched alkoxycarbonyl radical having from 1 to 6 carbon atoms. Examples which may be given are: methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, tert-butoxycarbonyl, n-pentoxycarbonyl and n-hexoxycarbonyl. Preference is given to a straight-chain or branched alkoxycarbonyl radical having from 1 to 4 carbon atoms.
Preference is given to using compounds of the general formula (I) or (Ia)
in which
R1 is phenyl, furyl, thienyl, triazolyl, pyridyl, cyclopentyl or cyclohexyl or is a radical of the formula
where the abovementioned ring systems are optionally mono- or disubstituted, identically or differently, by substituents chosen from the group consisting of halogen, trifluoromethyl, nitro, SO2xe2x80x94F3, methyl, cyano, trifluoromethoxy, hydroxyl, carboxyl, methoxycarbonyl or radicals of the formula xe2x80x94COxe2x80x94NHxe2x80x94CH2xe2x80x94C(CH3)3, xe2x80x94COxe2x80x94NH(CH2)2OH, xe2x80x94COxe2x80x94NHxe2x80x94CH2xe2x80x94C6H5, xe2x80x94COxe2x80x94NHxe2x80x94C6H5, xe2x80x94COxe2x80x94NHxe2x80x94(pOH)xe2x80x94C6H4, xe2x80x94Oxe2x80x94CH2xe2x80x94C6H5 or xe2x80x94Sxe2x80x94pClxe2x80x94C6H4,
R2 is a radical of the formula xe2x80x94XR12 or xe2x80x94NR13R14,
wherein
X is a bond or an oxygen atom,
R12 is hydrogen, (C1-C4)-alkenyl, (C1-C4)-alkoxycarbonyl or (C1-C4)-alkyl which are optionally substituted by pyridyl, cyano, phenoxy, benzyl or by a radical of the formula xe2x80x94NR15R16,
wherein
R15 and R16 are identical or different and are hydrogen, benzyl or (C1-C4)-alkyl,
R13 and R14 are identical or different and are hydrogen, (C1-C4)-alkyl or cyclopropyl,
R3 is hydrogen, amino or a radical of the formula 
or
is formyl, cyano, hydroxy-substituted (C1-C4)-alkylthio, trifluoromethyl, cyclopropyl or pyridyl, or
is (C1-C4)-alkyl, which is optionally substituted by halogen, (C1-C4)-alkoxycarbonyl, hydroxyl or by triazolyl, which for its part can be substituted up to 3 times by (C1-C4)-alkoxycarbonyl,
and/or alkyl is optionally substituted by groups of the formula xe2x80x94OSO2xe2x80x94CH3 or (CO)axe2x80x94NR17R18,
wherein
a is a number 0 or 1,
R17 and R18 are identical or different and are hydrogen, phenyl or benzyl, or are C1-C4-alkyl, which is optionally substituted by (C1-C4)-alkoxycarbonyl, amino, hydroxyl, phenyl or benzyl, where phenyl or benzyl are optionally mono- or polysubstituted, identically or differently, by hydroxyl, carboxyl, (C1-C4)-alkyl or (C1-C4)-alkoxy, and/or (C1-C4)-alkyl is optionally substituted by radicals of the formula xe2x80x94NHxe2x80x94COxe2x80x94CH3 or xe2x80x94NHxe2x80x94COxe2x80x94CF3,
or
R17 and R18 together with the nitrogen atom form a morpholine, piperidinyl or pyrrolidinyl ring,
or
R3 is phenyl, which is optionally substituted by methoxy,
or
R2 and R3 together form a radical of the formula
R4 is hydrogen, methyl, vinyl or acetyl, and,
R5 is pyridyl, pyrimidyl or pyrazinyl,
and their salts
in the control and prophylaxis of hepatitis B.
Particular preference is given to using compounds of the general formulae (I) and (Ia),
in which
R1 is phenyl, furyl, thienyl, triazolyl, pyridyl, cyclopentyl, cyclohexyl or is a radical of the formula
where the abovementioned ring systems are optionally substituted up to twice, identically or differently, by substituents chosen from the group consisting of fluorine, chlorine, bromine, iodine, hydroxyl, trifluoromethyl, nitro, SO2xe2x80x94CF3, methyl, cyano, trifluoromethoxy, carboxyl, methoxycarbonyl or radicals of the formula xe2x80x94COxe2x80x94NHxe2x80x94CH2xe2x80x94C(CH3)3, xe2x80x94COxe2x80x94NH(CH2)2OH, xe2x80x94COxe2x80x94NHxe2x80x94CH2xe2x80x94C6H5, xe2x80x94COxe2x80x94NH(C6H5, xe2x80x94COxe2x80x94NHxe2x80x94(pOH)xe2x80x94C6H4, xe2x80x94Oxe2x80x94CH2xe2x80x94C6H5 or xe2x80x94Sxe2x80x94pClxe2x80x94C6H4,
R2 is a radical of the formula xe2x80x94XR12 or xe2x80x94NR13R14,
wherein
X is a bond or an oxygen atom,
R12 is hydrogen, (C1-C3)-alkenyl, (C1-C4)-alkoxycarbonyl or (C1-C4)-alkyl, which are optionally substituted by pyridyl, cyano, phenoxy, benzyl or by a radical of the formula xe2x80x94NR15R16,
wherein
R15 and R16 are identical or different and are hydrogen or methyl,
R13 and R14 are identical or different and are hydrogen, (C1-C3)-alkyl or cyclopropyl,
R3 is hydrogen, amino or is a radical of the formula
or
is formyl, cyano, hydroxy-substituted (C1-C4)-alkylthio, trifluoromethyl, cyclopropyl or pyridyl, or
is (C1-C4)-alkyl, which is optionally substituted by fluorine, chlorine, (C1-C3)-alkoxycarbonyl, hydroxyl or by triazolyl, which for its part can be substituted up to 3 times by (C1-C3)-alkoxycarbonyl,
and/or alkyl is optionally substituted by groups of the formula xe2x80x94OSO2xe2x80x94CH3 or (CO)axe2x80x94NR17R18,
wherein
a is a number 0 or 1,
R17 and R18 are identical or different and are hydrogen, phenyl or benzyl, or are (C1-C3)-alkyl, which is optionally substituted by (C1-C3)-alkoxycarbonyl, amino, hydroxyl, phenyl or benzyl, where phenyl or benzyl are optionally mono- or disubstituted, identically or differently, by hydroxyl, carboxyl, (C1-C3)-alkyl or (C1-C3)-alkoxy, and/or (C1-C4)-alkyl is optionally substituted by radicals of the formula xe2x80x94NHxe2x80x94COxe2x80x94CH3 or xe2x80x94NHxe2x80x94COxe2x80x94CF3,
or
R17 and R18 together with the nitrogen atom form a morpholine, piperidinyl or pyrrolidinyl ring,
or
R3 is phenyl, which is optionally substituted by methoxy,
or
R2 and R3 together form a radical of the formula
R4 is hydrogen, methyl, vinyl or acetyl, and
R5 is pyridyl, pyrimidyl or pyrazinyl,
and their salts
in the control and prophylaxis of hepatitis B.
Very particular preference is given to using novel compounds of the general formulae (I) and (Ia).
in which
R1 is phenyl or triazolyl, which are optionally substituted up to twice, identically or differently, by fluorine, chlorine, bromine or iodine,
R2 is straight-chain or branched alkoxycarbonyl having up to 4 carbon atoms,
R3 is methyl, ethyl or cyclopropyl,
or
R2 and R3 together form a radical of the formula
R4 is hydrogen, vinyl or acetyl,
and
R5 is pyridyl,
in the prophylaxis and control of hepatitis B.
The present invention also relates to novel substances, which are listed in Table A:
Preference is given to using the novel compounds which are listed in Table B.
The novel compounds can exist in stereoisomeric forms, which behave either as image and mirror-image (enantiomers), or which do not behave as image and mirror-image (diastereomers). The invention relates to both the enantiomers or diastereomers or their corresponding mixtures. The racemic forms, like the diastereomers, can likewise be separated into the stereoisomerically uniform constituents by a known method.
The novel substances can also be in the form of salts. For the purposes of the invention, physiologically acceptable salts are preferable.
Physiologically acceptable salts can be salts of the novel compounds with inorganic or organic acids. Preference is given to salts with inorganic acids, such as, for example, hydrochloric acid, hydrobromic acid, phosphoric acid or sulphuric acid, or salts with organic carboxylic or sulphonic acids, such as, for example, acetic acid, maleic acid, fumaric acid, malic acid, citric acid, tartaric acid, lactic acid, benzoic acid, or methanesulphonic acid, ethanesulphonic acid, phenylsulphonic acid, toluenesulphonic acid or naphthalenedisulphonicacid.
Physiologically acceptable salts can likewise be metal or ammonium salts of the novel compounds. Particular preference is given, for example, to sodium, potassium, magnesium or calcium salts, and to ammonium salts derived from ammonia or organic amines such as, for example, ethylamine, di- or triethylamine, di- or triethanolamine, dicyclohexylamine, dimethylaminoethanol, arginine, lysine, ethylenediamine or 2-phenylethylamine.
The novel compounds of the general formulae (I) and the novel compounds (Table A) can be prepared
by reacting
[A] aldehydes of the general formula (II)
xe2x80x83R1xe2x80x94CHOxe2x80x83xe2x80x83(II)
in which
R1 is as defined above,
with amidines of the formula (III) 
in which
R5 is as defined above,
and compounds of the general formula (IV)
R3xe2x80x94COxe2x80x94CH2xe2x80x94COxe2x80x94R2xe2x80x83xe2x80x83(IV)
in which
R2 and R3 are as defined above,
optionally in the presence of inert organic solvents with or without the addition of base or acid,
or reacting
[B] compounds of the general formula (V) 
in which
R1, R2 and R3 are as defined above,
with amidines or their hydrochlorides of the general formula (III) 
in which
R5 is as defined above,
optionally in the presence of inert organic solvents at temperatures between 20xc2x0 C. and 150xc2x0 C. with or without the addition of base or acid,
or reacting
[C] aldehydes of the general formula (II)
R1xe2x80x94CHOxe2x80x83xe2x80x83(II)
in which
R1 is as defined above,
with compounds of the general formula (VI) 
in which
R2 and R3 are as defined above,
and amidines of the general formula (III) as described above,
or reacting
[D] aldehydes of the general formula (II) with compounds of the general formula (IV) and imino ethers of the general formula (VII) 
in which
R5 is as defined above,
and
R1 is (C1-C4)-alkyl,
in the presence of ammonium salts.
The preferred novel process [A] can be illustrated by way of example by the following equation:
[A]
For all process variants A, B, C and D, suitable solvents are all inert organic solvents. These include, preferably, alcohols, such as ethanol, methanol, isopropanol, ethers, such as dioxane, diethyl ether, tetrahydrofuran, glycol monomethyl ether, glycol dimethyl ether or acetic acid, dimethylformamide, dimethyl sulphoxide, acetonitrile, pyridine and hexamethylphosphoric triamide.
The reaction temperatures can be varied within a relatively large range. Usual temperatures are between 20 and 150xc2x0 C., but preferably at the boiling temperature of the particular solvent.
The reaction can be carried out at amospheric pressure, or at increased pressures. The pressure used is generally atmospheric pressure.
The reaction can be carried out with or without the addition of base or acid, although it has been shown that, for the purposes of the invention, a reaction preferably takes place in the presence of relatively weak acids, such as, for example, acetic acid or formic acid.
The aldehydes of the general formula (II) used as starting materials are known or can be prepared by methods known from the literature [cf. T. D. Harris and G. P. Roth, J. Org. Chem. 44, 146 (1979), Deutsche Offenlegungsschrift 2 165 260, July 1972, Deutsche Offenlegungsschrift 2 401 665, July 1974, Mijano et al., Chem. Abstr. 59, (1963), 13 929 c, E. Adler and H.-D. Becker, Chem. Scand. 15, 849 (1961), E. P. Papadopoulos, M. Mardin and Ch. Issidoridis, J. Org. Chem. Soc. 78, 2543 (1956)].
The ylidene-xcex2-keto esters of the formula (V) used as starting materials can be prepared by methods known in the literature [cf. G. Jones, xe2x80x9cThe Knoevenagel Condensationxe2x80x9d, in Organic Reactions, Vol. XV, 204 ff. (1 967)].
The enaminocarboxylic esters of the formula (VI) and the imino ethers of the general formula (VII) used as starting materials are known and can be prepared by methods known in the literature [cf. S. A. Glickman and A. C. Cope, J. Am. Chem. Soc. 67, 1017 (1945)].
The xcex2-ketocarboxylic esters of the general formula (IV) used as starting materials are known or can be prepared by methods known in the literature [e.g. D. Borrmann, xe2x80x9cUmsetzung von Diketen mit Alkoholen, Phenolen und Mercaptanenxe2x80x9d [Reaction of diketenes with alcohols, phenols and mercaptans], in Houben-Weyl, Methoden der organischen Chemie, Vol. VII/4, 230 ff (1968); Y. Oikawa, K. Sugano and O. Yonemitsu, J. Org. Chem. 43, 2087 (1978)].
The compounds of the general formula (III) can be prepared by reacting compounds of the formula (VIII)
R5xe2x80x94CNxe2x80x83xe2x80x83(VIII)
in which
R5 is as defined above,
as usual via the imino ethers and finally with ammonium chloride in methanol [cf. in this respect in analogy to W. K. Fife, Heterocycles 22, 93-96 (1984); T. Sakamoto, S. Kaneda, S. Nishimura, H. Yamanaka, Chem. Pharm. Bull. 33,565,571 (1986)].
All of the process steps take place at atmospheric pressure and in a temperature range from 0xc2x0 C. to 130xc2x0 C., preferably from 20xc2x0 C. to 100xc2x0 C.
The compounds of the general formula (VIII) are known per se.
The antiviral action of the novel compounds was determined in accordance with the methods described by Sells et al. (M. A. Sells, M.-L. Chen, and G. Acs (1987) Proc. Natl. Acad. Sci. 84, 1005-1009) and Korba et al. (B. E. Korba and J. L. Gerin (1992) Antiviral Research 19, 55-70).
The antiviral tests were carried out in 96-well microtitre plates. The first vertical row of plates contained only growth medium and HepG2.2.15 cells. This served as virus control.
Stock solutions of the test compounds (50 mM) were firstly dissolved in DMSO, and further dilutions were prepared in HepG2.2.15 growth medium. The novel compounds were usually pipetted in a test concentration of 100 xcexcM (1st test concentration) in each case into the 2nd vertical test row of the microtitre plate and then diluted in doubling steps to 210 fold in growth medium plus 2% of foetal calf serum (volume 25 xcexcl).
Each well of the microtitre plate then contained 225 xcexcl of a HepG2.2.15 cell suspension (5xc3x97104 cells/ml) in growth medium plus 2% of foetal calf serum.
The test batch was incubated at 37xc2x0 Celsius, 5% CO2, for 4 days.
The supernatant was then removed by suction and discarded, and the wells received 225 xcexcl of freshly prepared growth medium. The novel compounds were added in each case again as 10-fold concentrated solution in a volume of 25 xcexcl. The mixtures were incubated for a further 4 days.
Prior to harvesting the supernatants for determining the antiviral effect, the HepG2.2.15 cells were investigated for cytotoxic changes using a light microscope or using biochemical detection methods (e.g. Alamar blue stain or Trypan blue stain). The supernatants were then harvested and sucked by means of a vacuum onto 96-well dot blot chambers covered with nylon membrane (in accordance with the manufacturer""s instructions).
Substance-induced cytotoxic or cytostatic changes in HepG2.2.15 cells were determined as changes in cell morphology using, for example, a light microscope. Such substance-induced changes in HepG2.2.15 cells compared with untreated cells were visible, for example, as cell lysis, vacuolization or modified cell morphology. 50% cytotoxicity (Tox.xe2x88x9250) means that 50% of the cells have a morphology comparable with the corresponding cell control.
The compatibility of some of the novel compounds was additionally tested on other host cells, such as, for example, HeLa cells, primary peripheral human blood cells or transformed cell lines such as H-9 cells.
No cell-cytotoxic changes were found at concentrations of the novel compounds of  greater than 10 xcexcM.
After the supernatants had been transferred onto the nylon membrane in the blot apparatus (see above), the supernatants of the HepG2.2.15 cells were denatured (1.5 M NaCl/0.5 N NaOH), neutralized (3 M NaCl/0.5 M Tris HCl, pH 7.5) and washed (2xc3x97SSC). The DNA was then baked onto the membrane by incubating the filter at 120xc2x0 C. for 2-4 hours.
The detection of the viral DNA from the treated HepG2.2.15 cells on the nylon filter was usually carried out using non-radioactive, digoxigenin-labelled hepatitis B-specific DNA probes, which have each been labelled with digoxigenin, purified and used for hybridization in accordance with the manufacturer""s instructions. Prehybridization and hybridization took place in 5xc3x97SSC, 1xc3x97blocking reagent, 0.1% of N-lauroylsarcosin, 0.02% of SDS and 100 xcexcg of herring sperm DNA. The prehybridization took place for 30 minutes at 60xc2x0 C., and the specific hybridization with 20-40 ng/ml of the digoxigenated, denatured HBV-specific DNA (14 hours, 60xc2x0 C). The filters were then washed.
Immunological detection of the digoxigenin-labelled DNA took place according to the manufacturer""s instructions.
The filters were washed and prehybridized in a blocking reagent (according to the manufacturer""s instructions). Hybridization was then carried out with an anti-DIG antibody, which had been coupled with alkaline phosphatase, for 30 minutes. After a washing step, the alkaline phosphatase substrate, CSPD, was added incubated for minutes with the filters, then packed into plastic film and incubated for a further minutes at 37xc2x0 C. The chemiluminescence of the hepatitis B-specific DNA signals was made visible by exposing the filter to an X-ray film (incubation depending on the signal strength: from 10 minutes to 2 hours).
The half-maximum inhibitory concentration (IC-50, 50% inhibitory concentration) was determined as the concentration at which, compared with an untreated sample, the hepatitis B-specific band has been reduced by 50% by the novel compound.
Treatment of the hepatitis B virus-producing HepG2.2.15 cells with the novel compounds surprisingly led to a reduction in the viral DNA which is discharged into the cell culture supernatant from the cells in the form of virions in the cell culture supernatant.
The novel compounds show a novel, unforeseeable and useful effect against viruses. They have a surprising antiviral action against hepatitis B (HBV) and are thus suitable for the treatment of virus-induced diseases, in particular of acute and chronically persistent HBV viral infections. A chronic viral illness caused by HBV can lead to symptoms of varying severity; as is known, chronic hepatitis B virus infection in many cases leads to cirrhosis of the liver and/or to hepatocellular carcinoma.